LTC3858-1: Low IQ, Dual 2-Phase Synchronous Step-Down Controller Data Sheet12/2/2010428K
Features and Benefits
- Low Operating IQ: 170μA (One Channel On)
- Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
- Wide VIN Range: 4V to 38V
- RSENSE or DCR Current Sensing
- Out-of-Phase Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
- OPTI-LOOP® Compensation Minimizes COUT
- Phase-Lockable Frequency (75kHz-850kHz)
- Programmable Fixed Frequency (50kHz-900kHz)
- Selectable Continuous, Pulse-Skipping or Burst Mode® Operation at Light Loads
- Very Low Dropout Operation: 99% Duty Cycle
- Adjustable Output Voltage Soft-Start
- Power Good Output Voltage Monitor
- Output Overvoltage Protection
- Output Latch-Off Protection During Short Circuit
- Low Shutdown IQ: 8μA
- Internal LDO Powers Gate Drive from VIN or EXTVCC
- No Current Foldback During Start-Up
- Tiny 4mm × 5mm QFN and Narrow SSOP Packages
The LTC3858-1 is a high performance dual step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of up to 850kHz. Power loss and noise due to the input capacitor ESR are minimized by operating the two controller outputs out of phase.
The 170μA no-load quiescent current extends operating life in battery powered systems. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3858-1 features a precision 0.8V reference and a power good output indicator. A wide 4V to 38V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries.
Independent soft-start pins for each controller ramp the output voltages during start-up. The output latch-off feature protects the circuit in short-circuit conditions.
For a leadless 32-pin QFN package with the additional features of adjustable current limit, clock out, phase modulation and two PGOOD outputs, see the LTC3858 data sheet.
|Features||Adjustable Current Limit, Clock Output, Phase Modulation, 2 PGOOD Outputs||Fixed Current Limit, One PGOOD Output||Overvoltage protection crowbar and short-circuit latchoff disabled|
- Automotive Systems
- Battery Operated Digital Devices
- Distributed DC Power Systems
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 1352A is a low quiescent current, dual output 2-phase, synchronous buck converter demo board featuring the LTC3857EGN-1 or LTC3858EGN-1. It features a 4.5V to 36V input voltage range and provides 3.3V / 5A and 8.5V / 3A outputs. Two versions of the board are available. The DC-1352A-A is for the LTC3857EGN-1, which offers lower quiescent current and smaller burst mode ripple, while the DC1352A-B is for the LTC3858EGN-1 which offers latch-off protection and increased burst mode efficiency.
Documentation & Resources
R526 Reliability Data3/26/2018365 K
DC1352A - Demo Board10/22/20091M
Tools & Simulations
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LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
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LTpowerCAD Project Files
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ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
|Part Number||Material Declaration||Reliability Data||Pin/Package Drawing||CAD Symbols, Footprints & 3D Models|
|LTC3858EGN-1#PBF||Material Declaration||Reliability Data||28-Lead SSOP (Narrow 0.15 Inch)|
|LTC3858EGN-1#TRPBF||Material Declaration||Reliability Data||28-Lead SSOP (Narrow 0.15 Inch)|
|LTC3858EUFD-1#PBF||Material Declaration||Reliability Data||28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)|
|LTC3858EUFD-1#TRPBF||Material Declaration||Reliability Data||28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)|
|LTC3858IGN-1#PBF||Material Declaration||Reliability Data||28-Lead SSOP (Narrow 0.15 Inch)|
|LTC3858IGN-1#TRPBF||Material Declaration||Reliability Data||28-Lead SSOP (Narrow 0.15 Inch)|
|LTC3858IUFD-1#PBF||Material Declaration||Reliability Data||28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)|
|LTC3858IUFD-1#TRPBF||Material Declaration||Reliability Data||28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)|
|Wafer Fabrication Data||R526 Reliability Data|
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